Plasma polymerisation apparatus

A plasma polymerisation apparatus comprising:

• a reaction zone;
• at least one gas inlet for supplying at least one monomer in a gaseous form to the reaction zone;
• a first electrode and a second electrode spaced apart and configured to generate an electric field in the reaction zone to form a plasma-polymer nanoparticulate material from the at least one monomer;
• a plurality of collectors configured to collect the plasma-polymer nanoparticulate material formed in the reaction zone, the plurality of collectors being located adjacent the second electrode and each of the plurality of collectors being three-dimensionally shaped and defining a recess to receive the plasma-polymer nanoparticulate material formed in the reaction zone;
• a cooling device located adjacent the second electrode and configured to cool the plurality of collectors;
• and
• a confinement grid for confining the electric field in the reaction zone, wherein the confinement grid extends between the first electrode and the second electrode, wherein the confinement grid comprises a mesh having a plurality of openings, and wherein the confinement grid has a tubular or part-tubular structure and a maximum width that is substantially the same as a maximum width of the first and/or second electrodes.